The purpose of this research is to determine if exposure to relatively high noise levels produced by nearby jetplane traffic has, in children, detrimental effect on their physical growth. Here physical growth is a measure of child health in the community. The health consequences of chronic exposure to noise levels in residential areas, but equivalent to levels found in occupations of heavy industry or to levels used in laboratory experiments on non-humans, are not known. Children may be affected since they are likely to have spent a large proportion of their lives in the noisy environment and during that period they are susceptible to many environmental influences. Growth data are obtained through anthropometric examinations performed at the local elementary schools on approximately 300-500 subjects (age 5 through 12 years) from communities near an international airport where noise levels have been measured and are known to be high. Data on other factors which may also affect growth (e.g., birthorder, family size, family income, etc.,) are obtained from children's families in a personal interview at the home and from school records. The community has been divided into zones of noise exposure based on measurements of noise levels in the community and the analysis will compare physical growth in these zones to each other and to a similar but more remote community. The influence of other growth affecting variables will be considered and, if necessary, controlled statistically through an analysis of covariance, or through a matched pair study design.